U.S. patent number 5,502,982 [Application Number 08/234,576] was granted by the patent office on 1996-04-02 for cryogenic tie pin.
This patent grant is currently assigned to Liquid Carbonic Industries Corporation. Invention is credited to Jim M. Venetucci.
United States Patent |
5,502,982 |
Venetucci |
April 2, 1996 |
Cryogenic tie pin
Abstract
A cryogenic freezing tunnel having a conveyer belt, insulated
panels, each panel comprised of an inner metal surface layer, a
wooden layer, a foam insulation layer, an outer metal surface
layer, and tie pins connecting the outer and inner metal surface
layers together, thereby, preventing void spaces between the inner
metal layers and the wooden layers of the panels, which leads to
ice build-up and bulging of the inner metal surface which forces
collection pans and conveyer belt supports mounted on top the inner
metal surfaces upward into the conveyer belt and consequently
causes damage to the collection pans, conveyer belt supports, and
conveyer belt.
Inventors: |
Venetucci; Jim M. (Forest Park,
IL) |
Assignee: |
Liquid Carbonic Industries
Corporation (Chicago, IL)
|
Family
ID: |
22881949 |
Appl.
No.: |
08/234,576 |
Filed: |
April 28, 1994 |
Current U.S.
Class: |
62/374; 312/236;
312/406; 403/408.1; 411/384; 411/389 |
Current CPC
Class: |
F17C
3/04 (20130101); F25D 3/11 (20130101); F25D
23/06 (20130101); Y10T 403/75 (20150115) |
Current International
Class: |
F17C
3/00 (20060101); F17C 3/04 (20060101); F25D
3/11 (20060101); F25D 3/10 (20060101); F25D
23/06 (20060101); F25D 017/02 () |
Field of
Search: |
;62/63,374,375,380,45.1
;403/408.1 ;411/383,384,389 ;312/236,406 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Capossela; Ronald C.
Attorney, Agent or Firm: Lee, Mann, Smith, McWilliams,
Sweeney & Ohlson
Claims
What is claimed is:
1. A cryogenic freezing tunnel wherein said tunnel has overhead
sprayers for releasing cryogenic liquids onto foods, and insulated
panels, each panel being comprised of multiple layers of materials,
a conveyor belt and a compressing means for compressing the layers
of materials together, said compressing means comprising:
a rod having two rod ends made of material having low thermal
conductivity for minimizing heat loss from said tunnel and
formation of ice on said rod ends; and
two female inserts made of material having low thermal
conductivity, each said insert having a head portion and a female
end, said female ends being connected to said rod ends.
2. A cryogenic freezing tunnel according to claim 1 wherein the two
said rod ends are threaded, and said two female ends are
threaded.
3. A cryogenic freezing tunnel according to claim 1 wherein the
head portion of said female inserts have a slot.
4. A cryogenic freezing tunnel according to claim 1 wherein the
head portion of said female inserts has a keyed opening.
5. A cryogenic freezing tunnel according to claim 1 wherein said
rod is non-metallic.
6. A cryogenic freezing tunnel according to claim 1 wherein said
panels are welded together.
7. A cryogenic freezing tunnel having overhead sprayers for
releasing cryogenic liquids on to foods, wherein said tunnel also
has insulated panels and a conveyor belt, said insulated panels
comprising:
an outer skin layer abutting against a foam insulation layer; said
foam insulation layer abutting against a wood layer, said wood
layer abutting against an inner skin layer; and
a plurality of cryogenic tie pins, each said tie pin being made of
material having low thermal conductivity and having a rod and two
female inserts, each said insert having a head portion and a female
end, said female ends being connected to said rod ends, said tie
pins connecting said outer skin to said inner skin layer.
8. A cryogenic freezing tunnel according to claim 7 wherein the two
said rod ends are threaded, and said two female ends are
threaded.
9. A cryogenic freezing tunnel according to claim 7 wherein the
head portion of said female inserts have a slot.
10. A cryogenic freezing tunnel according to claim 7 wherein the
head portion of said female inserts has a keyed opening.
11. A cryogenic freezing tunnel according to claim 7 wherein said
rod is non-metallic.
12. A cryogenic freezing tunnel according to claim 7 wherein said
panels are welded together.
13. A cryogenic tie pin made of material having low thermal
conductivity for minimizing heat loss and ice formation on said
pins, comprising:
a rod made of said material having low thermal conductivity, said
rod having two rod ends: and
two female inserts made of said material having low thermal
conductivity, said inserts having a head portion and a female end,
said female ends being connected to said rod ends.
14. A cryogenic tie pin according to claim 13 wherein said two rod
ends are threaded, and said two female ends are threaded.
15. A cryogenic tie pin according to claim 13 wherein the head
portion of said female inserts have a slot.
16. A cryogenic tie pin according to claim 13 wherein the head
portion of said female inserts has a keyed opening.
17. A cryogenic freezing tunnel according to claim 13 wherein said
rod is non-metallic.
Description
BACKGROUND OF THE INVENTION
This invention generally relates to insulation panels for low
temperature liquified gas cryogenic freezing tunnels and spirals.
Cryogenic freezing tunnels are used for freezing food products. A
tunnel is composed of elongated insulted panels and a conveyer belt
mounted inside and to the floor of the tunnel. Food products which
move through the tunnel on the conveyer belt are quickly frozen by
contact with liquid nitrogen or other cryogenic liquid sprayed from
over head spray headers mounted in the tunnel as the food products
pass through the tunnel on a conveyer belt.
The spray headers are located on the inside ceiling of the tunnel.
These spray headers release liquid nitrogen N.sub.2 or other
cryogenic media onto the food products passing below on the
conveyer belt. The liquid nitrogen contacting the food quickly
freezes the food. The remainder of the liquid nitrogen falls onto
collection pans located below the conveyer belt and vaporizes.
The walls of the tunnel are made from insulated panels. The
insulted panels of the tunnel are made from multiple layers of
material. These layers of materials include an outside layer of
metal, a thick layer of foam insulation adjacent the outside metal
layer, a layer of plywood abutting the foam insulation, and an
inside metal skin abutting the plywood. The conveyer belt has
conveyer belt supports mounted onto the inside skin of the floor of
the tunnel. The collection pans are mounted to the floor of the
insulated tunnel. This construction allows food to be frozen
quickly as the food travels on the conveyer belt through the
tunnel.
However, in operation several problems may arise. Air tends to
accumulate in void spaces between the plywood and inside metal skin
due to openings in welded seams or cracks. The accumulation of the
air has the potential of condensing into oxygen due to the
temperature differentials between the inside of the freezer tunnel
and the void spaces. The moisture in the air condenses and
transforms into ice crystals which steadily expand in size.
When air having moisture in it infiltrates the void spaces in the
panel, two different conditions occur. First, the moisture
condenses due to the extreme difference in temperature and
transforms into ice, constantly increasing in size until the panels
buckle, damaging the weld seams thereby, allowing more air to enter
the void spaces causing even larger blocks of ice to form. This
cycle repeats itself causing further damage to the freezer tunnel.
This expansion of H.sub.2 O causes ice build-up between the plywood
and inside metal skin, therefore causing bulging of the external
surfaces of the inside metal skin, as well as cracking of the
welded seams. Since both the collection pans and support brackets
are mounted on the inside metal skin, the collection pans and
support brackets are forced upward by the bulging of the external
surfaces of the inside metal skin, thereby, forcing the collection
pans and conveyer belt supports upward into the conveyer belt
causing belt damage, breakage of conveyer belt supporting frames,
thereby, resulting shutdown of the cryogenic freezer tunnel.
The second condition can occur when the internal freezer
temperature approaches cryogenic temperatures of-280.degree. F. to
-320.degree. F., thereby, causing air in the void spaces to
separate into oxygen and nitrogen. This concentration of oxygen in
the void spaces can contribute to the combustion of the
insulation.
In accordance with the present invention, the problems of ice
build-up and bulging of the inside metal skin can be alleviated by
connecting the outer metal skin and the inner surface of the
freezer with cryogenic tie pins. The tie pins act to keep the inner
metal skin compressed against the wooden layers in the panels, and
thereby, limits the number of void spaces between the inner surface
and wooden layer. Consequently, this limits ice build up beneath
the inner surface which causes bulging and consequential break down
of the conveyer belt. Additionally, seams created by connecting the
panels together are welded together to prevent breathing of air
within the insulated chamber, thereby, further minimizing
condensing of moisture. Also, the problem of the combustion of foam
insulation is minimized. The cryogenic tie pins have low thermal
conductivity. The low conductivity of the tie pins minimizes heat
loss and formation of ice on the ends of the tie pins.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of the bottom panel of a cryogenic
freezer tunnel having cryogenic tie pins, and also showing
collection pans mounted thereto, and a conveyer belt mounted
thereto.
FIG. 2 is a sectional view of a cryogenic tie pin connecting the
outer and inner surfaces of a cryogenic freezer panel together.
Also shown is a sectional view of an L-Shaped panel
reinforcement.
FIG. 3 is a top, side, or bottom view of a cryogenic freezer tunnel
showing the outer surface and the heads of tie pins.
FIG. 4 is a sectional view of the bottom panel of a cryogenic
freezer tunnel not having cryogenic tie pins, and having bulges
created by ice build up between the inner skin of the panel and the
plywood, also showing collection pans forced upward into bottom of
conveyer belt and conveyer belt supports forced upward.
DESCRIPTION OF PREFERRED EMBODIMENT
Referring to FIG. 1, a conveyer belt 2 is mounted inside a
cryogenic freezer tunnel 4. The tunnel 4 is comprised of four
insulated panels 6, those panels being two side panels 6c, a top
panel 6a, and a bottom panel 6b. The conveyer belt 2 is mounted to
the bottom panel 6b by conveyer belt supports 8. Also, mounted to
the bottom panel 6b are collection pans 10. Attached to the
collection pans 10 are collection pan supports 10a which are
directly attached to and supported by the bottom panel 6b. The
insulated panels 6 have a plurality of tie pins 12 connecting outer
surface 14 of the panels 6 with the inner surface 16 of the panels
6. Also, overhead sprayers 17 are mounted to the top panel 6a. The
overhead sprayers 17 are used to release cryogenic liquids onto
food moving on the conveyer belt 2.
As better seen in FIG. 2, is an insulated panel 6 having a
cryogenic tie pin 12 connecting the outer surface 14 of the panels
6 with the inner surfaces 16 of the panels 6. The panel 6 is
comprised of a metal inner skin 18, against a layer of plywood 20,
the plywood 20 abuts against a layer of foam insulation 22, the
foam insulation 22 is enclosed by a metal outer skin 24. Each panel
6 has L-Shaped reinforcements 26 extending adjacent and along the
inside edges of the outer skin 24. The layers 18, 20, 22 and 24 of
the insulated panel 6 are connected together by tie pins 12. The
tie pins 12 consist of two threaded female portions 28 and a
threaded male rod 30. The female portions 28 have a head 28a at one
end and a threaded opening 28b at the other end. The head 28a of
the female portion 28 may have a slotted head 28b as seen in FIGS.
2-3, or the female portion 28 may have a keyed opening 28c as seen
in FIG. 2-3.The male rod 30 is threaded at each end 30a, with each
end 30a adapted to be screwed into the threaded opening 28b of a
female portion 28. The layers 18, 20, 22 and 24 of the insulted
panel 6 are compressed together by twisting either of the two
female portions 28 of a tie pin 12 around the male rod 30, thereby,
compressing layers 18, 20, 22 and 24 together. After compressing
the layers 18, 20, 22 and 24 together, the heads 28a of the female
portions 28 of each tie pin are welded to the surfaces of the metal
inner 18 and outer skins 24 (also see FIG. 3).
As see in FIG. 4, when cryogenic tie pins 12 are not used, ice 32
develops between the inner skin 18 and the plywood 20 causing the
inner skin 18 to buckle and push outward. The collection pans 10
mounted on the inner skin 18 are forced outward into the conveyer
belt 2. The ice build up 32 under the inner skin 18 also forces the
conveyer belt supports 8 upward to where the conveyer belt 2
becomes distorted.
* * * * *